These ads have been appearing for me as well for about the past month or so. It typically loads after a second or so after the main page loads. Most of the time in sets of 3 on the right sidebar with the "class="sideGridBox ad" as Rhana has shown above and sometimes as a horizontal ad near the top of the page with certain page layouts (the "new" slickdeals). Just like with OP, the box goes away when first attempting to block "class="sideGridBox ad" but it comes back after refresh.

Present in both Win 7 and OSX on Chrome running Adblock Plus extension with an up-to-date EasyList. It does not seem to appear on Android Firefox with Adblock Plus add-On also running EasyList.

Rules seem to be working as intended on Win 7 Firefox with Adblock Plus.

Checked another machine running Win 7 Chrome w/ Adblock plus and the problem persists however. Seems at least to be a Chrome related issue as I was able to reproduce it on 3 machines and it's fine on Firefox on 2 platforms.

ABP found a way around that site's workaround. Hopefully it will be in an upcoming release, and then AdBlock can use the same fix. In the meantime, are there any filters we can be suggesting to our users?

Rhana
AdBlock Community Manager

Posting on behalf of AdBlock (not ABP), when users come to us first and we have some reason to get involved with the discussion. http://help.getadblock.com